Lossless compression is still a form of compression but for 99.9% of well-exposed photographs, most people will find it extremely hard to see any difference between Sony compressed, uncompressed and DNG.

Hi, I’m a software engineer, I just wanted to provide some information as the answer above isn’t completely accurate.

TL;DR “is there any loss when converting the uncompressed RAW to DNG?”

NO! Zero loss at all, when converted to TIFF they will be identical pixel for pixel so long as you do not have the “Use lossy compression” option checked in the DNG converter. Now the long version…

Not exactly. Well, yes, it is indeed a form of compression but to say “it’s still a form of compression” is a misleading statement based on the context of the question you were responding to. Lossless compression is completely and 100% indistinguishable from an uncompressed file. Once uncompressed, they are bit for bit, completely identical (and if anyone’s wondering, in the case of lossless compression the data is completely useless to anything other than the decompression algorithm in the compressed state). The only functional difference is that the file is required to go through a decompression algorithm before the imaging software can use the file and this requires additional processing time. On the other hand, a file saved with lossless compression is smaller so less time will be spent reading it from the media. As to the performance difference you will see between the two… it will only be present whilst reading and decompressing the file. Once decompressed, performance will be the say with both.

Well then, which one is faster, DNG or uncompressed? I don’t know. Processor speed and storage medium will be the two main variables there. You might see the same overall performance for a machine with an SSD drive but a slower processor compared to a machine with a faster processor and a mechanical hard drive. To test it you could convert say 500 images to JPEG in two batches, one uncompressed RAW and the other DNG. Time both of them and that will give you your answer (for your specific hardware configuration).

Another example to illustrate the difference… a lossless compressed image file is pretty much the same as taking your uncompressed RAW file and zipping it. When you unzip it, you have a bit for bit identical copy of the original. DNG is the same, it’s just that with the DNG format Adobe is saving you the trouble of having to unzip and import all your uncompressed files. The DNG format also allows the convenience of embedding an image preview.

So… uncompressed RAW and DNG will identical when compared pixel for pixel. Compressed RAW (specifically speaking of Sony’s version) and uncompressed RAW will have differences in image quality.

Cost wise, DNG or compressed RAW will represent a dramatic savings if you’re a full time professional generating thousands of files every week. The caveat is that if you’re converting to DNG, you should not delete your original uncompressed RAW files until you’ve edited, and converted your images.

My second choice would be Fotodiox Adapter for Canon EF to Sony E-Mount. It appears to be essentially a clone of the old Metabones Smart Adapter III (with FW 0.31) – but unlike Metabones Smart adapter IV it’s stuck in time roughly 24 months ago with no way to update it’s firmware.

I pretty much base all my purchases on your reviews. I have the original A7 with the two primes the 35mm Zeiss and the 55mm Zeiss. I shoot a lot of portrait and landscape. I don’t care about 4k and don’t need to crop in my shots. So with that being said I bought the A7Rii, and took some shots. I honestly couldn’t tell much of a difference between the two. CS6 and Lightroom can not read the raw files from the A7Rii. I even updated Lightroom 6 and updated and still no raw. Anyways I am just thinking I am going to stick with the lighter smaller A7. I don’t need 4K, 5 Axis, or 42mp. Cheers

Just got the Sony a7RII and want to learn the different features, etc. Thank you for your information. I’ve read different ways to download the firmware update for RAW. One suggested saving to a formatted card and inserting that in the camera and another suggests plugging the camera into the computer. What do you think is the best way to download and install the update? Thanks.

Hi,
I was trying to find more information on the uncompressed RAW files of Sony cameras, as I come to a different conclusion when calculating the file size of my images.
I have a Sony a7II, which shoots 24 MP. With 14 bit colour depth and three channels of colour, each pixel should require 42 bit of memory when saving. For the whole image that is 1008 Mbit or 126 Mbyte. The uncompressed RAW files however only have 42 Mbyte.
Hence there must still be a considerable amount of compression, or am I getting something wrong here?

Hello Brian. When I import my A7RII images into Lightroom I can see the “flat” image, then within seconds Lightroom applies what looks like some sort of preset correction to the images. Is there a way to import the images without Lightroom applying this correction? The images were taken uncompressed with the Sony PP7 profile. Thank you in advance for your help!

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Pulitzer Prize-winning photographer Brian Smith creates iconic portraits of the famous and infamous for magazines, books and advertising. He has appeared on The X Factor, Fine Living Network and Israel Channel One and exhibited at the Library of Congress and the Aperture Gallery.